On 13 Sep 2005, at 16:22, David Roundy wrote:
On Tue, Sep 13, 2005 at 01:45:52PM +0000, Dhaemon wrote:
Also, just for kicks, may I had this: I read the code of some
haskell-made
programs and was astonished. Yes! It was clean and all, but there
were "do"s
everywhere... Why use a function language if you use it as an
imperative
one?(i.e. most of the apps in http://haskell.org/practice.html)
Monadic code isn't synonymous with imperative code, and "do" only
indicates
that you're looking at monadic code. The Maybe monad is an example
of a
very useful, very non-imperative monad that can be used to cleanly
write
functional code.
On the other hand, IO is always monadic, so perhaps you're looking
at IO
code. But I'd assert that even monadic IO code isn't quite the
same as
true "imperative" code. I'd probably say that the difference has
to do
with whether you create modifiable "variables". When you start
doing that,
whether you're in the ST monad or the IO monad, I think you're writing
imperative-style code. But I think that that sort of usage is
actually
pretty uncommon.
I would tend to argue that even in those monads you aren't really
writing imperative style code -- you still can't have side effects.
The point of the monad is that it preserves referential transparency
while doing something ordered.
Bob
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